Nonsteroidal anti-inflammatory drugs (NSAIDs) are on of the most widely prescribed class of medications. While generally safe, this class of medications may be associated with serious gastrointestinal and renal adverse effects, both there efficacy and toxicity is attributed to the inhibition of cyclo-oxygenase (COX). Cyclo-oxygenase has recently been discovered to exist in two isoforms COX-1 which is involved in maintenance prostaglandins and COX-2 which is involved in the production of inflammatory prostaglandins. Currently available nonsteroidal anti- inflammatory drugs (NSAIDs) have been characterized as dual COX-1 and COX-2 inhibitors [1,2]. This is a double-blind, placebo-controlled, multicenter, double-dummy, parallel group study to evaluate and compare the effects of multiple doses of the selective COX-2 inhibitor MK-0966, indomethacin, and placebo on renal function in subjects 65 to 80 year of age with creatinine clearance 30 to 80 ml/minute.